JP4230063B2 - Rotating body molding method and molding die - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding method and a molding die for a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape, such as a friction wheel, a roller bearing, a roller, a pulley, and a gear.
[0002]
[Prior art]
For example, in a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape, such as a friction wheel or a roller bearing, as shown in FIG. 8 (a), a rotating body 81 having a flat outer peripheral surface, or (b) As shown in the rotating body 82 whose outer peripheral surface is slightly inclined, as shown in (c), the rotating body 93 in which the diameter of the peripheral edge is slightly larger, as shown in (d), As shown in the rotating body 84 whose outer peripheral surface is concave or the rotating body 85 whose outer peripheral surface is slightly inclined with respect to the rotating shaft, as shown in FIG. Stress concentration occurs due to contact with each other at the edge or protrusion of the part. In addition, uneven rotation, wear, noise, and the like are generated due to the contact. In order to solve such a problem, for example, as shown in FIG. 9 (a), the end of the roller-like rotating body 91 is formed into a crowning shape with a small curvature, or the rotating body as shown in FIG. 9 (b). The outer peripheral surface 91 is formed into a convex curved surface. The crowning shape and the convex curved surface are usually processed by grinding or tumbling. Grinding is not easy to work and takes a long time. Tumbler processing has good workability, but the processing accuracy decreases. For this reason, in the crowning method disclosed in Japanese Patent Laid-Open No. 7-171744, an initial crowning having an approximate size is formed by tumbling, and then the initial crowning portion is finished to the final crowning by superfinishing.
[0003]
[Problems to be solved by the invention]
As described above, the crowning shape can be processed with high precision by superfinishing after tumbler processing, but it takes a lot of processing time to cut a rotating body such as a roller bearing and the rotating body becomes expensive. It is difficult to apply to the processing.
[0004]
In order to mass-produce rotary bodies such as friction wheels, roller bearings, and gears at low cost, it is suitable to form synthetic resin by molding. However, since the outer peripheral surface of the rotating body having the crowned shape at the end of the outer peripheral surface is convex, the molded product cannot be taken out unless the mold is divided within the outer peripheral surface when molding, It has been difficult to mold roller bearings and gears that require accuracy in the shape and dimensions of the outer peripheral surface.
[0005]
This invention can improve such disadvantages, and can easily mass-produce low-priced rotary bodies such as friction wheels, roller bearings, gears, etc. with the crowned outer peripheral surface and the convex outer peripheral surface. An object of the present invention is to provide a method for molding a rotating body and a molding die .
[0006]
[Means for Solving the Problems]
A method for forming a rotating body according to the present invention is a molding method for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape, and a rim that is an annular ring portion on the outer periphery of the molded product in a solidification step. The surface connecting the rim of the member connecting the rim and the central shaft portion is preferentially cooled to form sink marks on the surface connecting the rim of the member connecting the rim and the central shaft portion. The surface end is formed into a crowning shape.
[0011]
Another molding method of the rotating body according to the present invention is a molding method for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape, in an annular ring portion on the outer periphery of the molded product in a solidification step. A rim of a member for connecting a rim and the central shaft portion by supplying pressurized fluid to a portion of the member that connects the rim and the central shaft portion, pressurizing the molded product by the supplied pressurized fluid; Sink marks are formed on the connecting surfaces , and the outer peripheral surface of the rim is formed into a convex curved surface.
[0013]
A molding die for a rotating body according to the present invention is a molding die for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape, and a rim that is an annular ring portion on the outer periphery of the molded product. A cooling piece that circulates a cooling medium is provided between the mold to be formed and the mold that forms a portion that connects the rim of the member that connects the rim and the central shaft portion .
[0014]
Another molding die of the rotating body according to the present invention is an annular ring portion on the outer periphery of the molded product in the molding die for forming the molded product of the rotating body formed in a cylindrical shape, a columnar shape, or a disk shape. characterized in that a fluid supply unit for supplying a molded article pressurize pressurized fluid between a mold for forming the portion connecting the rim of the member for connecting the mold and the rim and the central axis portion forming a rim And
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Rotating bodies such as friction wheels, roller bearings, and pulleys whose outer peripheral surface is formed in a cylindrical shape are produced by molding, and have a crowning shape with a small curvature at the surface end of the cylindrical outer peripheral surface. Has a forcibly formed sink on the surface.
[0016]
The molding die for producing the rotating body has a cooling piece in the vicinity of the outer peripheral surface of the rotating body of the fixed side mold plate and the movable side mold plate forming the outer peripheral surface divided by the mold dividing surface. When forming a rotating body with this molding die, a cooling medium is supplied to the cooling pipe of the cooling piece in the solidification process to cool the cooling piece, and the portion forming the vicinity of the outer peripheral surface of the rotating body is forcibly cooled. Thus, sink marks are forcibly generated in a portion forming the vicinity of the outer peripheral surface. When this sink begins to occur, the end of the outer peripheral surface is caused by the tensile force acting on the end of the outer peripheral surface of the rotating body by the tensile force of the semi-solid material on the surface of the sink and the force to supplement the material of the sink. The crowning shape is automatically formed on the part.
[0017]
【Example】
FIG. 1 is a sectional view showing an embodiment of the present invention. As shown in the drawing, a rotating body 1 such as a friction wheel, a roller bearing, and a pulley having an outer peripheral surface formed in a cylindrical shape is manufactured by molding, and a crowning shape 3 having a small curvature at a surface end portion of the cylindrical outer peripheral surface 2. And has sink marks 5 forcibly formed on a surface other than the outer peripheral surface 3, for example, the inclined surface 4 of the rim at the outer peripheral portion. As a molding material for producing the rotating body 1, a resin such as a crystalline resin, an amorphous resin, an elastomer, a thermosetting resin, an energy curable resin, or a moldable low melting point metal or a mixture is used. Among the ceramic materials that can be sintered later, a material having the property of shrinking when the material is solidified is used.
[0018]
Usually, as shown in FIG. 2A, when a part is formed by molding, the molding material 6 filled in the molding die and heated is cooled and solidified in the solidification step. The molding material 6 of this molding die begins to solidify as it cools from the surface layer part in contact with the mold, and the cooling is slowest at the center 7 of the thickest part, the T-shaped part, and the base of the rib. To solidify. Thus, when the molding material 6 is solidified, the solidified part is accompanied by volume shrinkage, and thus the pressure is reduced. As shown in FIG. When the pressure is reduced, a force f that pulls the surrounding material is generated, and the material of the portion that is most easily pulled is pulled to the central portion 7 or the like. If the tensile force f causes sink marks 5 and the molding material 6 moves away from the surface of the mold, cooling due to heat conduction to the mold is hindered, and the temperature of the portion is difficult to decrease. The temperature rises due to the heat from the material, and the viscosity of the material also decreases, making it easier to move. For this reason, sink marks 5 become more prominent. The position where the sink marks 5 are generated is determined by the shape, thickness, aspect ratio, etc. of the molded product, and the sink marks 5 are likely to be generated on the outer peripheral surface of the cylindrical, columnar or disk-shaped molded product. When the position 8 where the sink marks 5 are generated is controlled in the vicinity of the outer peripheral surface of the molded product as shown in FIG. 3A, the molding material 6 in the molding die is at the controlled position 8 and the outside is the central portion 7. 3B, sink marks 5 are generated as shown in FIG. 3 (b), and when the sink marks 5 are generated, a tensile force F is applied to an end portion in the vicinity of the sink marks 5, and an end portion of the outer peripheral surface. Thus, the crowning shape 3 having a small curvature is formed.
[0019]
Thus, in order to control the position where sink marks 5 are generated during molding, the molding die 10 for producing the rotating body 1 has an outer peripheral surface divided by a mold dividing surface 11 as shown in the partial sectional view of FIG. Cooling pieces 14 and 15 are provided in the portion of the outer peripheral portion of the rotating body 1 of the fixed side mold plate 12 and the movable side mold plate 13 forming the inclined surface 4 of the rim. The cooling pieces 14 and 15 are provided with cooling pipes 16 for circulating a cooling medium sent from the cooling device.
[0020]
When the rotating body 1 is molded with the molding die 10 configured as described above, a cooling medium is supplied to the cooling pipes 16 of the cooling pieces 14 and 15 in the solidification process to cool the rotating body 1 as shown in FIG. The pieces 14 and 15 are cooled, and the portion of the outer peripheral portion of the rotator 1 that forms the inclined surface 4 of the rim is forcibly cooled. By this cooling, the surface portion of the portion forming the inclined surface 4 becomes semi-solidified and drawn into the central portion, and as shown in FIG. 4 (b), the portion forming the inclined surface 4 of the rim on the outer peripheral portion is forced. The sink marks 5 are formed at the end. When this sink mark 5 starts to be generated, the tensile force F acting on the end portion of the outer peripheral surface 2 of the rotating body 1 by the tensile force F of the semi-solidified material on the surface portion of the sink mark 5 and the force for supplementing the material of the sink mark 5 portion. The crowning shape 3 is automatically formed at the end of the outer peripheral surface 2 by the force. Therefore, the rotating body 1 having the crowning shape 3 at the end of the outer peripheral surface 2 can be easily formed and manufactured. Further, since the crowning shape 3 is produced in the molding die 10 by using the sink marks 5 of the molding material, it is not necessary to provide the mold dividing surface in the outer peripheral surface 2 of the rotating body 1 and the outer peripheral surface 2 of the rotating body 1. Can be formed with high accuracy. In this way, when the crowning shape 3 is formed at the end of the outer peripheral surface 2 of the rotating body 1 by using the generation of sink marks 5, solidification and shrinkage are particularly large when a crystalline resin material is used as a molding material. The crowning shape 3 can be produced effectively.
[0021]
The size of the crowning shape 3 and the range to be formed vary depending on the size of the sink marks 5 and the thickness and cross-sectional shape of the portion where the sink marks 5 are generated. ), The central portion of the outer peripheral surface 2 is flat, and only the end portion of the outer peripheral surface 2 has the crowning shape 3. When the influence of sink marks 5 is large, the range in which the crowning shape 3 is formed becomes large, and the outer peripheral surface 2 becomes a convex curved surface with the center protruding. Therefore, the crowning shape 3 can be formed in the desired range of the outer peripheral surface 2 by changing the size of the cooling pieces 14 and 15 and the cooling temperature according to the molding material.
[0022]
Although the said Example demonstrated the case where the cooling pieces 14 and 15 were provided in the shaping die 10 which produces the rotary body 1, and the position which the sink mark 5 generate | occur | produced was controlled, as shown in the fragmentary sectional view of FIG. Fluid supply pieces 17, 18 are provided on the fixed side mold plate 12 and the movable side mold plate 13 of the mold 10, and fluid is supplied to the fluid supply pieces 17, 18 in the solidification process, and sink marks 5 are generated from the fluid supply port 19. Alternatively, fluid may be introduced into the portion to forcibly generate sink marks 5 by fluid pressure, and the crowning shape 3 may be formed at the end of the outer peripheral surface 2 of the rotating body 1 by the generated sink marks 5. In this case, it is desirable to supply liquid to the fluid supply pieces 17 and 18 depending on gas or molding material which does not affect the environment such as pressurized air and nitrogen gas.
[0023]
Although the said Example demonstrated the case where the sink 5 was generated in the inclined surface 4 of the outer periphery of the rotary body 1, and the crowning shape 3 was formed in the edge part of the outer peripheral surface 2, (a) of sectional drawing of FIG. Friction wheel 1a shown in FIG. 3) or top bearing shown in FIG. 2B or sink 1 is generated on the side surface adjacent to the outer peripheral surface 2 of the roller 1b to form the crowning shape 3 at the end of the outer peripheral surface 2. .
[0024]
Further, when a gear is formed as a rotating body, as shown in the perspective view of FIG. 7, by controlling so that sink marks 5 are formed on the side surfaces of the teeth 21 and the rim 22 of the gear 1 c, The outer peripheral surface, the tooth profile side surface, and both ends of the tooth bottom can be formed into a crowning shape 3. Therefore, it is possible to form the gear 1c that can prevent stress concentration at one end or at the outer peripheral edge during use with high accuracy and at low cost.
[0025]
【The invention's effect】
As described above, in the present invention, when a rotating body formed in a cylindrical shape, a columnar shape, or a disk shape is formed , a rim that is an annular ring portion on the outer periphery of a molded product and a central shaft portion are formed in a solidification process. By preferentially cooling the portion to be connected to the rim of the connecting member, supplying pressurized fluid, and pressurizing the molded product with the supplied pressurized fluid, sink marks can be easily generated at a desired position. It is possible to create a stable crowning shape at the end of the outer peripheral surface of the molded product, or to form the outer peripheral surface into a convex curved surface with a certain shape , preventing stress concentration at the edge of the piece or at the outer peripheral end during use Can be easily created.
[0026]
In addition, since the crowning shape and the convex curved surface are produced in the molding die using sink marks of the molding material, it is not necessary to provide the mold dividing surface in the outer peripheral surface of the rotating body, and the outer peripheral surface of the rotating body is accurately formed. can do.
[0027]
In addition, by generating sink marks on the surface that connects the rim of the annular ring portion on the outer periphery and the rim of the member that connects the central shaft portion , a complicated shape such as a roller bearing, roller, pulley, etc. with a small outer diameter is formed. It is possible to easily form a product that can prevent stress concentration at one end or at the outer peripheral end during use with a gear or the like.
[0029]
In addition, a cooling part is provided between a mold that forms a rim that is an annular ring part on the outer periphery of a molding product of a molding die and a mold that forms a part that connects a rim of a member that connects the rim and the central shaft part. By providing the fluid supply part that supplies or supplies the fluid that pressurizes the molded product , the position where the sink mark is generated can be reliably controlled.
[0030]
Furthermore, by controlling the cooling temperature of the cooling unit and the pressure of the fluid supplied to the fluid supply unit, the size of the sink marks generated can be controlled, and the crowning of a desired size can be applied to the outer peripheral surface end of the molded product. A shape can be created, or the outer peripheral surface can be formed into a convex curved surface having a desired shape.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a rotating body according to an embodiment of the present invention.
FIG. 2 is an explanatory view showing a state in which sink marks are generated in a molding material during molding processing.
FIG. 3 is an explanatory diagram showing the state of sink marks that occur when the position at which sink marks occur is controlled.
FIG. 4 is a partial cross-sectional view showing a molding die and a molded product for molding the rotating body of the embodiment.
FIG. 5 is a partial cross-sectional view of another molding die for molding the rotating body of the embodiment.
FIG. 6 is a cross-sectional view showing an example of a molded article of a rotating body.
FIG. 7 is a perspective view showing a position of sink marks generated in a molded product of a gear.
FIG. 8 is a partial cross-sectional view of a rotating body having an edge portion and a protruding portion at an end portion of a contact surface.
FIG. 9 is a partial cross-sectional view of a rotating body having a crowning shape at the end of the contact surface and a rotating body having a convex contact surface.
[Explanation of symbols]
1; rotating body, 2; outer peripheral surface, 3; crowning shape, 5; sink,
10: Molding die, 11: Mold dividing surface, 12: Fixed side template, 13: Movable side template,
14, 15; Cooling pieces, 17, 18; Fluid supply pieces.

Claims (4)

In a molding method for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape or a disk shape,
The rim of the member that connects the rim and the central shaft portion by preferentially cooling the surface connecting the rim of the member that connects the rim that is the annular ring portion on the outer periphery of the molded product and the central shaft portion in the solidification process. A method of forming a rotating body, wherein sink marks are formed on a surface to be connected to the outer periphery of the rim, and a surface end portion of the outer peripheral surface of the rim is formed into a crowning shape. In a molding method for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape or a disk shape,
Pressurized fluid is supplied to the rim of the member that connects the rim, which is an annular ring portion on the outer periphery of the molded product, and the central shaft portion in the solidification process, and the molded product is pressurized with the supplied pressurized fluid. A method for forming a rotating body, comprising: forming a sink on a surface of a member that connects a rim and a central shaft portion to a rim, and forming an outer peripheral surface of the rim into a convex curved surface. In a molding die for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape or a disk shape,
A cooling piece that circulates a cooling medium between a mold that forms a rim that is an annular ring portion on the outer periphery of a molded product and a mold that forms a portion that connects the rim and a rim of a member that connects the rim and the central shaft portion. A molding die characterized by that. In a molding die for forming a molded article of a rotating body formed in a cylindrical shape, a columnar shape or a disk shape,
Pressurized fluid that pressurizes the molded product between a mold that forms a rim that is an annular ring portion on the outer periphery of the molded product and a mold that forms a part that connects the rim and a rim of a member that connects the central shaft part. A rotating body molding die comprising a fluid supply section for supplying.

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